Mechanical fuze



June 20, 1961 H. JUNGHANS ETAL 2,988,995

MECHANICAL FUZE Filed Nov. 29, 1957 3 Sheets-Sheet 1 INVENTORS T7 1729 A1776 4- BY R frame/- m M V yJ'.

2,988,996 MECHANICAL FUZE Helmut Junghans, Schwarzwald 'Wurttemberg, Schramberg-Sulgen, and Paul Kaiser, Wurttemberg Weihergasse 28, Schramberg, Germany Filed Nov. 29, 1957, Ser. No. 699,777 Claims priority, application Germany Dec. 1, 1956 3 Claims. (Cl. 102-78) The invention relates to a fuze for unrotated rocket projectives, more especially of the graze fuze type. Rocket fuzes of this type can be based upon an acceleration period of about 0.8 second. In order that the fuze may be transported and loaded with safety and at the same time to ensure that the release functions may take place with the necessary safety after firing, a safety period of about 0.4 to 0.5 sec. must be provided. After about 0.6 sec., the acceleration decreases rapidly. It amounts to about 50 g. The accelerating forces are thus small in relation to those in normal artillery projectiles. However, since no other driving forces, for example centrifugal forces, are available, satisfactory safety of the fuze, whether it is constructed as a percussion fuze or as a self-destroying fuze, can be obtained only by utilising the longitudinal acceleration. The construction according to the invention is also based upon this principle. In this construction, primary importance is attached to satisfactory safety against all actions of intentional or accidental nature. The new fuze comprises in known manner a radially movable slide member for closing the passage for the ignition pin. The invention is characterised by a fixedly mounted bell-crank lever, of which one, substantially radially extending arm is-loaded, while the other, rearwardly extending arm co-operates partly with an inertia weight engaging laterally in its plane of rotation and braked by a known retarding mechanism, and partly acts as a pawl of a driving-ratchet mechanism, with which there is associated a resilient dog arranged on the forward side of the slide member for the closure of the passage of the ignition pin, the force storing means loaded at the latest at firing exerting on the bell-crank lever a restoring torque which is greater than the countertorque exerted by the restoring force acting on the slide member.

Further features of the invention concern the design of the time-controlled locking device for the bell-crank lever, as also the design of the control and transport safety means for the aforesaid slide member.

An embodiment of the invention as applied to a graze fuze will hereinafter be described with reference to the drawings, which are drawn in diagrammatic form to an enlarged scale, and in which:

FIGURE 1 shows the fuze in the inoperative state,

FIGURE 2 shows the fuze during the acceleration, and

FIGURE 3 shows the fuze in the live state after percussion.

l designates the fuze cap and 11 a base plate, on which the safety slide member 14 is so mounted as to be movable in the direction of the arrow 13. The said slide member closes off the aperture 11a in the plate 11 for the ignition pin 15 and is itself formed with an aperture 14a, which is situated behind the point of the ignition pin 15 in the live position, in order that the said pin may penetrate into the percussion cap (not shown) behind the plate 11. The slide member 14 is pushed by a spring 16 into the safety position in the direction opposite to the direction of the arrow 13 and is thus brought into contact with an abutment not shown. In the live position, the slide member 14 bears against the abutment 17.

The following parts serve partly to secure and partly to control the slide member 14: the bell-crank lever 19 nited States Patent 0 7 2,988,996 Patented June 20, 1961 is mounted on its fixed pin 18 in the fuze cap 10, and comprises a rearwardly extending arm 19a comprising laterally projecting lug 19b and a pinlike extension 195, as also a radially extending arm 19d. The arm 19d is subject to the action, on the one hand, of the recoil spring 20 and on the other hand of the inertia weight 21, which is adapted to be so mounted in the fuze as to be longitudinally slideable by means of the guide pins 21a and 21b. The force exerted on the bell-crank lever 19 by the inertia weight during the acceleration is intended to rotate the said lever in the counter-clockwise direction, while the recoil spring 20 is operative in the opposite sense. 1

While the recoil spring 20 and the inertia weight 21 serve to guide the bell-crank lever 19, the inertia weight plate 22 is provided to control the said lever. The said plate is mounted so as to be longitudinally movable in the fuse by means of a pin and slot guide and comprises an obliquely descending locking face 22a and a recess 22b adjoining the edge 22a of the said face.

For braking the inertia weight plate 22, the escapement mechanism consisting of the escape wheel 23 and the lever 24 is provided, which mechanism receives its drive from the inertia weight plate 22 through the pin-25,

the toothed rack 26 and the gear-wheel 27. The recoil spring 28 acts on the rack 26.

The extension on the bell crank lever 19 co-operates with the leaf spring 29 secured to the slide member 13 by the screw 30. The spring is bent forwardly at its free end and forms to some extent the dog of a driving pawl and ratchet mechanism, the pawl of which is formed by the extension 190 of the arm 19a of the bellcrank lever. When the bell-crank lever 19 is turnedin the counter-clockwise direction, the arm extension 194' pushes the leaf spring 29 down until the extension 190 slides over the edge 29a. When the bell-crank lever-19 subsequently returns in the clockwise direction, 190 presses on the edge 29a, which is then again upright and moves the slide member 14 into the live position in. the direction of the arrow 13.

In order to secure the slide member 14 in the inoperative position against lateral shocks arising in transport, the leaf spring 29 is formed with a bent-over arm 29b comprising a lug 29b. Formed in the inertia weight 21 for the lug 29b is a slot 210 extending parallel to the axis of the fuse, the opposed surfaces defining the slot serving as safety abutments. The slot 210 is adjoined by a passage 21d which widens towards its rear end. For this purpose, the inclined surface 21d is provided. The passage 21d is of such width that the lug 29b can pass therethrough.

The manner of operation of the fuze is as follows: in the inoperative position (FIGURE 1), the slide member 14 closes the percussion pin aperture 11a. The slide member is secured against lateral shocks, more especially against shock in the release direction 13, by virtue of the fact that the lug 29b lies in the slot 210 in the inertia weight 21. Consequently, the rocket cannot be fired by radial or axial shocks from the head or tail thereof.

When the acceleration commences, inertia forces are exerted on the weights 21 and 22, the back pressure of the weight 21 being suflicient to overcome the opposed action of the spring 20 and thus to compress the said spring. The same applies to the weight 22 and the spring 28. With sustained acceleration, the turning moment exerted on the bell-crank lever 19 by the back pressure holds the lever initially with its lug 19b bearing against the control face 22a. The downward inclination of the said control face is somewhat exaggerated in the drawing. The downward inclination is not intended to initiate a functionally necessary rotation of the lever 19,

but only to reduce the friction between the lever and its control means, that is to say, the extension 19:: of the lever arm remains in front of the spring 29a and bends the latter back somewhat as long as the lug 19b slides on the face 22a. Only when the lug 1% has fallen from the inclined edge 22a and has entered the recess Nib-the production of which condition is timed by the escapement mechanism 23 to 27--does a change occur in the co-operation between the lever 19 and the slide member 1 4. The extension 190 of the lever arm has then descended on the leaf spring edge 29a and the leafspring has been bent forwardly and upwardly again and now forms a dog for locking the part 190. Slide member 14 remains in the safety position during the acceleration, but the transport safety position has been cancelled, that is to say, the lug 29b now lies in the passage 21a.

When the axial acceleration ceases (FIGURE 3), the recoil spring 20 compressed by the inertia weight 21 is able to hold the bell-crank lever 19 together with the weight 21 in the initial position (FIGURE 1). spring 20 is sufiiciently strong to cause the bell-crank lever 19 to engage by means of its arm extension 190 with the edge 29a of the leaf spring and thus to bring the slide member 14 into the live position (FIGURE 3) against the spring 16, so that the aperture 14a is then situated behind the point of the percussion pin (in the position as illustrated, the percussion pin has already been forced to the rear by virtue of its percussion sensitivity).

The inertia weight 21 has been lifted somewhat in the forward direction from the bell-crank lever 19- under the action of the spring 20, but since the slide member 14 has simultaneously moved in the direction of the arrow 13, the lug 2% has been unable to return into the slot 210, but has moved into a position above the inclined surface 21d and has been able to slide down on this surface.

The design of the fuze according to the invention as a graze fuze has been described only by way of example. The fuze could alternatively be constructed as a selfdestroying fuze, in which case the slide member 14 could serve as a securing element for the balance wheel of a spring-driven self-destroying clockwork movement. It is to be noted that the component elements, which have only been diagrammatically illustrated for the sake of The' clarity, could consist of metal die casting or of plastic, if desired with metal guide and mounting parts.

We claim:

1. A fuze particularly for sensitive impact and nonrotary rocket projectiles comprising a fuze cap, a slide member slidable in the fuze cap in a direction at right angles to the longitudinal axis of the projectile, a striker pin slidable in the fuze cap and abutting against the slide member in its safety position, a bell crank lever having two arms and pivotally mounted in the fuze cap, an inertia weight member contacting with one arm of the bell crank lever in abutting contact therewith, a spring abutting against the slide member to urge the latter to its safety position, a spring abutting against the said one arm of the bell crank lever, an inertia weight plate slidable in the fuze cap and having a recess surface in contact with the other arm of the bell crank lever, braking means connected to the inertia weight plate to retard the sliding movement of the inertia weight plate, an extension rod connected to the said other arm of the bell crank lever, and a leaf spring secured on the slide member and against which the extensionrod normally abuts, said spring of the bell crank lever being stronger as to its spring force than the spring abutting against the slide member.

2. A fuze according to claim 1, in which means are provided secured on the inertia weight and connected to the slide member to secure the latter against untimely sliding movement thereof.

3. A fuze according to claim 1, in which a locking arm is secured on the slide member and in which an abutment is provided on the inertia weight to secure the locking arm and the slide lever against sliding movement until the slide member is set free by the movement of the locking arm.

References Cited in the file of this patent UNITED STATES PATENTS 2,685,253 Apotheloz Aug. 3, 1954 2,814,251 Kuhn Nov. 26, 1957 2,817,295 Wylie Dec. 24, 1957 2,863,393 Sheeley Dec. 9, 1958 FOREIGN PATENTS 752,991 Great Britain July 18, 1955 

